沪科版七年级上数学知识点总结.doc

沪科版七年级上数学知识点总结1

沪科版七年级上数学知识点总结(一)

2014年10月

第一章:有理数

一、有理数的意义

1-1正数和负数

1、为什么初中数学要引入负数,

答:正数和负数是在实际需要中产生的，我们可以用正数和负数来表示相反意义的量。

2、在生产和生活中，相反意义的量主要有哪些,请列举:

答:常见的有:(1)温度高于0度记作“+”，低于0度记作“-”。(2)高度高于海平面记作“+”，低于海平面记作“-”。(3)高于正常水位记作“+”，低于正常水位记作“-”。(4)超过标准重量记作“+”，低于标准重量记作“-”。(5)储蓄中存入为正，取installationpartmainincludingYunnanprovincetengchongCountyyongxingRiverprimaryandsecondaryhydropowerstationintheofpressurepipeandthepowerstationmetalstructure,whichlevelpowerstationpressurepipetotalabout562t(containingannex);IIlevelpowerstationpressurepipeabout733t(containingannex);levelpowerstationmetalstructureabout52.5t,containingdischargeGate2hole,rushedsandGate1hole,watermouthworkdoorandthestoppeddirtgatethe1hole,Qianpoolworkdoorandthestoppeddirtgatethe1hole;Secondarypowerstationmetaljunctionatabout19.5t,containingsandGate1hole,waterinletwatergateandtrashthe1hole;theirauxiliaryhoistequipmentandelectricalequipment.Concretepressurepipe,gate,trashandhoistingdeviceprojectpropertylist1-1~1-3.Table1-1themaincharacteristicsofthepenstocknumberitemparametertypecontrollersizeheadalongpipediameterpipelength11hydropowerstationpenstockopen-airexposedpipe,singlepipejointwatersupply1.3M931m0.8M8.3*2m22hydropowerstationpenstockopen-airexposedpipe,singlepipejointwatersupply1.4m1063.506m0.8M10*2mtable1-2hydropowerstationMaincharacteristicsofhydraulicmetalstructurenumberprojectnamegate,trashrack,door(gate...Pressurepipeandthemetalstructureinstallation9.1mainengineeringprofileyongxingriverlevelhydropowerstationpressurepipepipelineplaneShangalongRidgeislinelayout,andslopesurfacecontourclosevertical,GuanPowithoriginalgroundlinechanges,usedopentypeMingtube,singletubejointwaterway,competentdiameter1.3M,long931.00m,tworootnon-symmetricButypesupport